error: lifetime may not live long enough
  --> $DIR/ret-ty-borrowck-constraints.rs:5:5
   |
LL | fn link(x: &str) -> &'static str {
   |            - let's call the lifetime of this reference `'1`
LL |     become passthrough(x);
   |     ^^^^^^^^^^^^^^^^^^^^^ returning this value requires that `'1` must outlive `'static`

error: aborting due to 1 previous error